1. Field of the Invention
The present invention relates to a digital video signal processing, and more particularly, to a deinterlacing device and method for converting a video signal of an interlaced scan format into a video signal of a progressive scan format.
2. Description of the Related Art
Deinterlacing is typically classified as intra-field interpolation using spatial correlation or inter-field interpolation using intra-field information and inter-field information on the basis of the spatial correlation and temporal correlation to perform interpolation. The intra-field interpolation uses only the intra-field information on the basis of the spatial correlation to perform the interpolation, and is represented as a line repetition, a line average, an Edge-based Line Average (ELA) and the like. The inter-field interpolation uses the intra-field information and the inter-field information on the basis of the spatial correlation and the temporal correlation to perform the interpolation, and is represented as a motion compensated interpolation and a motion adaptive compensated interpolation. Generally, the inter-field interpolation is known in the art as having excellent performance, but has a disadvantage in that construction is complicated and price is high due to an additional field memory that is needed for use of the inter-field information. In contrast, the intra-field interpolation does not perform as well as inter-field interpolation, but has an advantage in that construction is simple and price is low.
Since the Line Average of the intra-field interpolation performs the interpolation by using an average value of upper and lower-direction pixels, jagging occurs at a low gradient edge, thereby causing picture quality to be degraded.
Since the ELA performs the interpolation by using edge information of an image, thereby effectively preventing the jagging from occurring at the edge of the image, it has a good performance in the intra-field interpolation. However, the ELA cannot detect an actual edge and can erroneously detect a direction at a region having a vertical edge, at a region where the image is not distinct in brightness difference, and at a region having many high-frequency components of the image. This causes the picture quality to be rather degraded due to the generation of a distinct erroneous high frequency component. Even though the ELS has an excellent interpolation performance, the ELS has a tendency to be used, due to the above disadvantages, in an intra-field interpolation device using a recent popularized motion adaptive way than a separate deinterlacing device. However, since much improvement is still required for the degradation of the picture quality, which is caused by erroneous interpolation, various ELSs are under development.